1. Field of the Invention
The present invention relates to systems for ensuring the quality of cleaning and maintenance services and, more particularly, to an inspection method and device.
2. Description of the Background
It is known that certain compounds are highly reflective of ultra-violet radiation, and this principle has been used to make certain dyes that are transparent in white light, yet luminous in ultra-violet light. For example, U.S. Pat. No. 3,589,280 to Wilde shows a device for coding containers by marking with normally transparent and invisible indicia. The containers are marked with ultraviolet ink that is normally invisible, but which becomes visible upon UV illumination.
This and other known verification/authentication applications require highly specific inks designed to adhere to the particular paper or article to be imprinted and to fluoresce at a particular wavelength. In most of these authentication applications it has also been necessary to employ specialized lighting to illuminate the ink. Such requirements are driven by the need to deter counterfeiters, and they result in relatively expensive authentication systems. Nevertheless, the cost is justified in light of the inherent value of the items being authenticated, e.g., currency.
Fluorescent inks have been used in other contexts, namely for artistic and novelty items. For instance, U.S. Pat. No. 5,698,614 to Uedae et al. shows an oil-based fluorescent ink composition which comprises propylene glycol monomethyl ether as a solvent a solution type fluorescent pigment dissolved in the organic solvent, and a ketone resin.
Likewise, ultra-violet lights have been used in other applications. For instance, U.S. Pat. No. 5,572,319 discloses a stain detector apparatus and method for detecting stains in a fabric using an incandescent lamp and a fluorescent lamp for projecting light rays toward the fabric.
Despite the above, many utilitarian applications for the concept have gone largely unnoticed because they are not justified by the expense in developing the proper inks and lighting. One particular application is in cleaning management and inspection. Various systems have been used as a quality assurance measure in the cleaning services industry. For example, electronic check points are now in wide use, and these require a cleaning person to register themselves using an electronic key, magnetic card reader or the like, at each station to be cleaned. While such approaches generally track the presence and progress of the cleaning person about their rounds, they fail to check the actual quality of the cleaning effort.
It would be greatly advantageous to make use of the properties of invisible fluorescent ink to provide a quality assurance measure for the cleaning industry by which management can ensure that certain areas are being thoroughly cleaned.
It is, therefore, an object of the present invention to provide a system by which management can ensure the quality of cleaning and maintenance services by physically inspecting whether invisible ink markings have been removed by a cleaning person.
It is another object to provide a variety of water-soluble invisible ink compositions that can be applied to a variety of common surfaces, all of which inks wash away upon normal cleaning.
It is still another object to provide a comprehensive cleaning management kit and method of using the same including economical and convenient applicators for the above-described inks, and economical and convenient illuminators for fluorescing the inks.
It is still another object to provide a cleaning management method for applying information to common surfaces using a special marking ink that contains a fluorescent material which is invisible under normal light but is visible upon being exposed to ultra violet rays, and for inspecting said surfaces using an ultra violet light to ensure that said information has been properly removed by cleaning personnel.
According to the present invention, the above-described and other objects are accomplished by providing various compositions of water-soluble invisible ink and various applicators therefor which are suited for a number of different surfaces. One formula is dispensed from a pen applicator is best suited for applying the ink to hard surfaces such as porcelain, FORMICA(copyright) laminate, metal, mirrors, tiles or other impervious surfaces in order to perform cleaning inspections on areas such as bathrooms, kitchens, offices etc. to ensure proper cleaning is being done.
Another formula dispensed from the same pen applicator uses less alcohol and is best suited for application to fabrics such as sheets, linens, drapes, furniture, wall partitions, etc. to ensure proper cleaning. This formula is gentler and ensures that the fabric is not damaged.
Another formula is provided in powder form for application via a roller applicator to carpets to ensure proper vacuuming. Certain plush and/or coated carpets would be better covered by a spray-applicator, and the present invention also provides a spray form and applicator suited for this purpose.
Still another formula is designed for application in wax crayon form to hard floorings or surfaces that might have a surface coating like wax (i.e. VCT, tile, wood or marble floors).
Despite the various compositions and method of application, all of the invisible inks are formulated so that they are not absorbed by the surface or fabric, but instead reside on top and are removed with normal cleaning. These ink compositions have many potential applications including the cleaning kit and method of the present invention. Additionally, the ink compositions in and of themselves are suitable for advertising that needs to be removed, such as nightly meal specials at a restaurants. They also provide an excellent toy to allow children to write secret or special messages that need to be removed, e.g., removable messages on the walls of their room or on clothes with that would only be visible under ultra violet light.
In the context of cleaning inspection according to the present invention, any one or all of these specially-formulated inks are combined in a kit with a convenient hand-held ultra-violet light. An area to be cleaned is marked with the appropriate invisible ink marker prior to cleaning. After the area has been cleaned an inspection is made with a ultra violet light to expose the original area marked and to determine whether the original mark is still there. If so, the area could not have been properly cleaned. However, if the original mark is gone then the area was cleaned.
The above-described system allows management to inspect the quality of cleaning and maintenance services by physically inspecting whether the invisible ink markings have been removed. The kit is simple to use as the inks are applied by convenient pen, powder or spray applicators, and a portable ultra-violet light is provided for fluorescing the inks. So long as the appropriate marking compound and applicator is used for a given surface, the method is completely non-destructive as the marking composition will wash away upon normal cleaning.